1. Field of the Invention
The present invention relates to an electrophotographic photosensitive member, a process cartridge, and an electrophotographic apparatus.
2. Description of the Related Art
An electrophotographic photosensitive member which contains an organic photoconductive material (charge generation material) is commonly used as an electrophotographic photosensitive member mounted on an electrophotographic apparatus. Since an electrical or mechanical external force such as charging, exposure, development, transfer, and cleaning is directly applied to the surface of an electrophotographic photosensitive member when an electrophotographic apparatus repeatedly performs image formation, the surface of the electrophotographic photosensitive member needs to have durability against the external force. Furthermore, the surface of the electrophotographic photosensitive member needs to have reduced friction force (lubricity and sliding properties) applied to a contacting member (e.g. cleaning blade).
In order to have lubricity, the use of a polycarbonate resin having a specific siloxane moiety for the surface layer of an electrophotographic photosensitive member is disclosed in Japanese Patent Application Laid-Open No. 2008-195905 and Japanese Patent Application Laid-Open No. 2006-328416. In Japanese Patent Application Laid-Open No. 2010-126652, a polyester resin having a specific siloxane moiety is disclosed.
As a result of investigation by the present inventors, it was found that there is room for improvement in positive memory when a resin (polycarbonate resin or polyester resin) having a siloxane moiety at the end as disclosed in Japanese Patent Application Laid-Open No. 2008-195905, Japanese Patent Application Laid-Open No. 2006-328416, and Japanese Patent Application Laid-Open No. 2010-126652 and a charge transporting substance having a specific structure as a charge transporting substance are used.
The positive memory is a memory phenomenon caused by positive charging (charging with positive charge) of the surface of an electrophotographic photosensitive member. Examples of the situation that the surface of an electrophotographic photosensitive member is positively charged include a case that an electrophotographic photosensitive member and a charging member or a cleaning blade in contact with the electrophotographic photosensitive member are subject to sliding friction under impact due to vibration or falling in physical distribution so that positive charges are generated on the surface of the electrophotographic photosensitive member, and a case of positive charging during transferring.